1. Field of the Invention
The present invention relates to a controller for controlling the operation of gripping devices of a grapple harvester bulk handling device.
2. Description of Related Art
The bulk handling device makes possible the processing of several tree trunks simultaneously. Bulk handling can improve the efficiency of harvesting thinning trees and thereby getting better thinning trees to the factory. At the same time the remaining trees make better progress in attaining lumber dimensions.
The harvester control equipment is very complicated and the operator has to make many decisions in a short time period. The more simply a function occurs the more operator time is saved for the important decision of selecting and removing the tree.
One aspect of the present invention is to introduce a controller for the bulk handling device where the commands controlling the functions of the device are arranged to take place automatically without specific actions by the operator.
In an embodiment of the controller according to the present invention, the valve controlling an operating device is connected to the operating device of a loader harvester""s cross-cutting device, and to a tilting mechanism of a tilting frame, and is arranged to operate in conjunction with the cutting device and felling so that the gripping devices are normally in the closed position. The gripping devices are arranged, at least in the felling position, to always open when the harvester head turns to the delimbing position, and to close immediately after the operation in question. In the controller for this type of bulk handling device, the cutting and felling operations directly and automatically control the opening and closing of the gripping devices without any special action by the operator.
In an arrangement according to the present invention, the controller may include a switch connected to the gripping devices with which the gripping devices can be mechanically moved into the open position. Where necessary, it is possible to intervene in their operation by opening the gripping devices by a manual operation. It is also possible to completely switch off the opening of the gripping devices when, for example, on a final felling site bulk handling is not utilized at all.
Additionally, the controller may include a warning light in the control cabin, or an equivalent signal on the display, which indicates when the bulk handling device is switched on. In this way the operator is always aware of the operational status of the bulk handling device.
In this manner, the operator may be freed to carry out the actual thinning and threshing work. Automated operation does not consume working time since it is carried out simultaneously alongside other necessary operations. In addition, erroneous operations are avoided, i.e., it protects the guide bar (the tree does not slip onto it) and the tree does not fall prematurely.